Patents by Inventor Robert A. Buhrman

Robert A. Buhrman has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 9105832
    Abstract: An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.
    Type: Grant
    Filed: August 17, 2012
    Date of Patent: August 11, 2015
    Assignee: Cornell University
    Inventors: Robert A. Buhrman, Luqiao Liu, Daniel C. Ralph, Chi-Feng Pai
  • Publication number: 20150200003
    Abstract: 3-terminal magnetic circuits and devices based on the spin-transfer torque (STT) effect via a combination of injection of spin-polarized electrons or charged particles by using a charge current in a spin Hall effect metal layer coupled to a free magnetic layer and application of a gate voltage to the free magnetic layer to manipulate the magnetization of the free magnetic layer for various applications, including non-volatile memory functions, logic functions and others. The charge current is applied to the spin Hall effect metal layer via first and second electrical terminals and the gate voltage is applied between a third electrical terminal and either of the first and second electrical terminals. The spin Hall effect metal layer can be adjacent to the free magnetic layer or in direct contact with the free magnetic layer to allow a spin-polarized current generated via a spin Hall effect under the charge current to enter the free magnetic layer.
    Type: Application
    Filed: August 6, 2013
    Publication date: July 16, 2015
    Inventors: Robert A. Buhrman, Daniel C. Ralph, Chi-Feng Pai, Luqiao Liu
  • Publication number: 20140169088
    Abstract: An ST-MRAM structure, a method for fabricating the ST-MRAM structure and a method for operating an ST-MRAM device that results from the ST-MRAM structure each utilize a spin Hall effect base layer that contacts a magnetic free layer and effects a magnetic moment switching within the magnetic free layer as a result of a lateral switching current within the spin Hall effect base layer. This resulting ST-MRAM device uses an independent sense current and sense voltage through a magnetoresistive stack that includes a pinned layer, a non-magnetic spacer layer and the magnetic free layer which contacts the spin Hall effect base layer. Desirable non-magnetic conductor materials for the spin Hall effect base layer include certain types of tantalum materials and tungsten materials that have a spin diffusion length no greater than about five times the thickness of the spin Hall effect base layer and a spin Hall angle at least about 0.05.
    Type: Application
    Filed: August 17, 2012
    Publication date: June 19, 2014
    Applicant: CORNELL UNIVERSITY
    Inventors: Robert A. Buhrman, Luqiao Liu, Daniel C. Ralph, Chi-Feng Pai
  • Patent number: 4654231
    Abstract: A method of producing high quality stoichiometric thin films of vanadium dioxide by reactive evaporation utilizes an electron beam to evaporate a source of vanadium in a controlled, low pressure oxygen gas environment with the film being deposited at a predetermined rate onto a substrate which is heated to and maintained at a predetermined temperature above 500.degree. C.
    Type: Grant
    Filed: May 21, 1985
    Date of Patent: March 31, 1987
    Assignee: The United States of America as represented by the Secretary of the Navy
    Inventors: Glen A. Nyberg, Robert A. Buhrman